Natural gas fireplace



FIG. 1 is a front perspective view of a natural gas fireplace showing my new design;

FIG. 2 is a front elevational thereof;

FIG. 3 is a rear elevation thereof;

FIG. 4 is a left side elevation thereof the right side being a mirror image thereof;

FIG. 5 is a top plan thereof; and,

FIG. 6 is a bottom plan thereof. 

The ornamental design for a natural gas fireplace, as shown and described. 